生物地球化学的概念与方法——DNDC模型的发展

生物地球化学作为一个学科包含4个概念,即生物地球化学量、流、群和场.这4个概念从不同角度描述了生命与其环境的关系.生物地球化学量探索生命及其无机环境在元素丰度上的相似性,这种相似性决定了生命体对环境化学状态的依赖性.生物地球化学流描写化学元素在生态系统中的迁移,此迁移导致了生命体与环境间的物质和能量交换.生物地球化学群描述化学元素在迁移转化时的复杂组合关系及其生物效应.生物地球化学场是生态系统中控制生物地球化学反应的各种环境营力的总和.生物地球化学模型即是这一综合力场及其对化学元素迁移转化影响的数学描述,DNDC模型即基于这些概念发展起来.DNDC模型可用来预测陆地生态系统中碳和氮的生物地球化学行为,该模型已被一些国家用来预测农业土壤的长期肥力和温室气体排放.     

生物地球化学的发展

生物地球化学作为地学的一门分支学科,是研究生物及其产物在自然界物质循环中的作用,研究无机质与有机质关系、能量输入与生物能量储存关系、能量释放和地球上主要矿物循环的科学。早在1548年Giordano Bruno提出循环发展的思想后,三十年代苏联学者维尔拉斯基提出了生物地球化学的概念。由于受到科学技术的限制,发展相当缓慢。直到近年来,由于生物学和地球化学研究领域的发展而迅速崛起,并在生物成矿论、元素循环和环境等方面取得了重大进展,才受到了人们的重视。     

黑色岩系成岩成矿过程中的生物地球化学作用

黑色岩系在其形成和发展中,特别是在成岩成矿过程中都离不开生物地球化学作用。通过对震旦纪一下古生代五套黑色岩系及其中四类矿床的矿物、岩石、地球化学及稳定同位素研究,从生物成矿的角度讨论了这些黑色岩系和矿床在成岩成矿过程中的生物地球化学作用,并强调生物地球化学元素循环及生物地球化学体系研究的重要性。     

雪冰中微量有机物的生物地球化学研究进展

雪冰中微量有机物的生物地球化学研究进展龙江平，秦大河（中国科学院冰川冻土研究所，兰州７３００００）关键词雪冰，有机物，生物地球化学雪冰中微量有机物的生物地球化学主要研究雪冰中有天然来源的微量有机物和由人类活动、工业化发展带来的人为污染有机物。通过雪冰...     

矿床生物地球化学勘探的主要模式

目前积累了大量有关生物地球化学探测矿床深度及其它特征的实际资料。这些资料的分析出现了矛盾。例如,疏松异地盖层的厚度不是生物地球化学晕形成的障碍,其变化从1m到200m。据研究Au、Sn、W、Be的生物地球化学晕,没有在所有类型的这些矿床上方出现。导致这些看似矛盾的重要原因之一是指示元素在土壤和岩石的根系带中存在的各种不同形式。指示元素的矿物形式与生物地球化学晕强度依赖性是一个要长期特别研究的课题。这     

全球生物地球化学循环研究的进展

简要介绍了全球元素生物地球化学循环研究的新进展。首先说明几十年来生物地球化学循环研究重点的转变，其次分析了当前研究的特点，这就是多层次地（时空及生态系统）进行实验和数学模拟并外推至全球，比经典的循环研究要细致得多，经典研究往往只是将定位点的结果简单地外推到区域甚至全球。最后有选择地阐述了生物地球化学循环各领域（源、汇、转化过程、测量方法、模式等）内的发展趋势与热点，其中主要有农业生态系统含碳、氮痕     

硅的生物地球化学循环研究进展

生命元素硅在陆地生态系统和水生生态系统中都扮演着重要的角色。它的生物地球化学循环与全球碳循环和全球气候交化密切相关。因此,近年来逐渐成为研究的热点。本文概述了近年来国内外有关硅的生物地球化学循环的研究进展,包括陆地和海洋中硅的生物地球化学循环过程及人类活动对硅循环的影响等方面,指出日前研究中存在的问题,展望了研究的重点。     

植物中汞的研究进展

植物生态系统中汞的环境过程是生物地球化学循环过程的重要组成部分，且与整个生态系统中各物种的生存和发展密切相关。本文介绍了植物中汞生物地球化学循环的进展，包括汞对植物的生物毒性、植物中汞的来源、分布与迁移转化、植物大气间汞的交换过程及其研究方法，以及植被在生态系统间汞循环中的重要作用，最后简要介绍今后的研究重点和热点。     

二氧化碳生物地球化学循环研究的进展

综述了对二氧化碳生物地球化学循环的研究现状，着重介绍了大气二氧化碳的源和汇的研究资料，并简要介绍了有关碳循环模式。     

中、新生代陆相沉积盆地生物地球化学循环、古环境与成矿

中新生代是地史上生物最为繁茂多样大发展和生物成矿的重要时期，陆相沉积盆地沉积岩中最为系统地保存了各种生物地化作用和过程的信息。研究中新生代陆相沉积的生物地球化学循环、古环境及成矿具有重要的意义，提出了开展该项研究的一些主要内容。     

Exploring the effects of urban and agricultural land use on surface water chemistry,across a regional watershed,using multivariate statistics

In this paper, the influence of anthropogenic activity on surface water chemistry is investigated. Base flow samples from dominant land use streams in the Muskegon River Watershed, Michigan, USA, were analyzed for nutrients, major ions, and trace elements. Principal component and hierarchical cluster analysis were used to investigate the processes controlling the effects of land use on the biogeochemistry of streams in this Watershed. Biogeochemical fingerprints of land use were developed based on the results of the cluster analysis. Spider diagrams which referenced the natural environment aided the identification of the individual contributions of urban and agricultural land uses to surface water chemistry. The biogeochemical fingerprints quantified support previous findings (Urb: Na, K, Cl/Ag: Ca, Mg) and produced new insights into the effects of land use on the behavior of nutrients (Ag: N and Urb: N, P) and trace elements (Urb: V, Cr, Co, Cu, Se, Rb, Mo, Sr, Cd, Pb and Ba/Ag: U and As). The higher correlations of urban than agricultural land uses with nutrients, specifically P, were not expected and may reflect the effects of fertilization and wastewater or the season the samples were taken. More study in different geologic and urban settings is needed to help refine these fingerprints, but it is becoming apparent that despite obscuring factors, land use produces consistent, quantifiable associations between biogeochemical analytes.     

生态系统营养离子循环及水化学演化的锶同位素示踪

综述了Ｓｒ同位素示踪生态系统离子循环和水化学演化的基本原理、主要内容和最新进展。着重介绍了Ｓｒ同位素在矿物风化速率研究、流域营养离子来源识别及其循环通量计算、地下水体化学成分演化机制的研究中的示踪应用;最后展望了Ｓｒ同位素在生物地球化学过程示踪上的潜在价值。     

生态系统营养离子循环及水化学演经的锶同位素示踪

综述了Ｓｒ同位素示踪生态系统离子循环水化学演化的基本原理、主要内容和最新进展。着重介绍了Ｓｒ同位素在矿物风化速率研究、流域营养离子来源识别及其循环通量计算、地下水体化学尬发演化机制的示踪应用;最后展望了Ｓｒ同位素在生物地球化学过程示踪上的潜在价值。     

Correlation of karst agricultural geo-environment with non-karst agricultural geo-environment with respect to nutritive elements in Guizhou

The karst area accounts for 61.9% of the total area in Guizhou Province, which gives rise to a fragile environment and backward economy. Comparative studies on the element contents of rock and soil and agriculture production in both carbonate area and non-carbonate area have been made to establish factors leading to low output and poor quality of agricultural products in the karst area. The result shows that there is an apparent lack of nutrient elements in carbonate rocks. The trace element contents of carbonate rocks are only 3532.27×10-6, but those of non-carbonate rocks are 10894.21×10-6. The available element contents in culti-vated soil delivered from carbonate rocks are merely 101.4×10-6, but those from non-carbonate rocks are 326.05×10-6. The available element contents and total element contents in cultivated soil delivered from non-carbonate rocks are 3 times higher than those from carbonate rocks. Besides, high-quality agricultural products such as rice, potato and tea are mainly produced in the non-carbonate area. It is indicated that the low output and quality of agricultural products are caused by the above-mentioned low trace element contents and poor agricultural environment. Therefore, a new method of mineral nutrients compensation has been put forward, which is very effective to raise the load-bearing capacity of agricultural environment, agricultural output and quality of agricultural products.     

贵州喀斯特与非喀斯特农业生态地质环境质量对比研究

为寻求喀斯特地区农产品低劣的根源,通过调查和采样测试对比研究了贵州碳酸盐岩和非碳酸盐岩地质环境和农作物产品质量的差异。结果表明:（1）非碳酸盐岩的微量元素含量为10.894 2×10-3,而碳酸岩的为35.322 7×10-4;非碳酸盐岩地区耕作土中有效态微量元素含量为3.260 5×10-4,碳酸盐岩分布区的耕作土仅为1.014×10-4,彼此相差3倍;（2）优质农作物多产于非碳酸盐岩地区,随机调查贵州省内38个优质水稻产地,有33个位于非碳酸盐岩地区,仅有5个在碳酸盐岩区。茶叶、马铃薯、西瓜等也有此类规律。由此认为,喀斯特环境缺乏多种矿物营养元素,是形成其农作物质量低下的根本原因,也是贵州喀斯特农业生态环境脆弱的内在原因。      

GEOTRACES - An international study of the global marine biogeochemical cycles of trace elements and their isotopes

Trace elements serve important roles as regulators of ocean processes including marine ecosystem dynamics and carbon cycling. The role of iron, for instance, is well known as a limiting micronutrient in the surface ocean. Several other trace elements also play crucial roles in ecosystem function and their supply therefore controls the structure, and possibly the productivity, of marine ecosystems. Understanding the biogeochemical cycling of these micronutrients requires knowledge of their diverse sources and sinks, as well as their transport and chemical form in the ocean.Much of what is known about past ocean conditions, and therefore about the processes driving global climate change, is derived from trace-element and isotope patterns recorded in marine deposits. Reading the geochemical information archived in marine sediments informs us about past changes in fundamental ocean conditions such as temperature, salinity, pH, carbon chemistry, ocean circulation and biological productivity. These records provide our principal source of information about the ocean's role in past climate change. Understanding this role offers unique insights into the future consequences of global change.The cycle of many trace elements and isotopes has been significantly impacted by human activity. Some of these are harmful to the natural and human environment due to their toxicity and/or radioactivity. Understanding the processes that control the transport and fate of these contaminants is an important aspect of protecting the ocean environment. Such understanding requires accurate knowledge of the natural biogeochemical cycling of these elements so that changes due to human activity can be put in context.Despite the recognised importance of understanding the geochemical cycles of trace elements and isotopes, limited knowledge of their sources and sinks in the ocean and the rates and mechanisms governing their internal cycling, constrains their application to illuminating the problems outlined above. Marine geochemists are poised to make significant progress in trace-element biogeochemistry. Advances in clean sampling protocols and analytical techniques provide unprecedented capability for high-density sampling and measurement of a wide range of trace elements and isotopes which can be combined with new modelling strategies that have evolved from the World Ocean Circulation Experiment (WOCE) and Joint Global Ocean Flux Study (JGOFS) programmes. A major new international research programme, GEOTRACES, has now been developed as a result of community input to study the global marine biogeochemical cycles of trace elements and their isotopes. Here, we describe this programme and its rationale.     

An integrative approach toward biosensing and bioremediation of metals and metalloids

The contamination of harmful metals and metalloids has emerged as a major issue of concern with the industrial and agricultural progress and increase in human population in the last century. Natural biogeochemical activities are also responsible for increase in the level of elements. Metal(loid)s reach to humans either directly through contaminated drinking water or through the food when crop is cultivated in contaminated areas. Metal(loid)s have carcinogenic, mutagenic, and toxicological properties and hence are a burden to body and the cause of a number of health problems. To combat the menace of metal(loid)s contamination, there is a need to not only precisely monitor their levels in the environment but also to remove them efficiently. In addition, these two basis processes require being a low-cost affair to be affordable for routine operation and for most of the areas and people. Biosensors and bioremediation are two important areas, which offer hope to achieve the goals by allowing sensing of metal(loid)s precisely and removing them at a low cost and in easily operable manner. The present article reviews progress of biosensor and bioremediation approaches and proposes prospective feasible strategies for future.     

河北阜平县表层土壤重金属对人体健康的风险评估

河北省阜平县矿产资源丰富,矿产开发会产生大量重金属污染物,近年来大力发展果农业,也会对表层土壤造成一定影响,目前该县表层土壤重金属现状尚不清晰.为评估阜平县农业重点区表层土壤重金属污染特征和对人体健康的影响,本文按照1:5万土地质量调查规范要求,布设标准网格在该县农业重点区采集表层土壤样品647组,采用原子荧光光谱、电...     

Research Advance of Changing Biogenic Substance Cycling in River Systems by Damming*

River damming transforms allotropic natural rivers into autotrophic 'impound river' (referred to "reservoir"), which changes the processes of river biogenic substance cycle and the matter properties as well as export flux from land to ocean, thus becoming one of the key problems of element biogeochemical cycle. Due to the different behavior of biogenic substances (C, N, P, Si) in biological processes, biogenic substances cycle efficiency is different, in turns, Silicon (Si)>Organic Carbon (OC)>Phosphorus (P). The migration and transformation processes of C and Si are significantly affected by phytoplankton and water retention time. Nitrogen (N) and P are mainly affected by water pH, temperature, Dissolved Oxygen (DO) and retention time. The retention efficiency of biogenic substances is shown as N>C>P>Si at the global scale. Besides, the sedimentation and burial processes of reservoirs constitute the net sink of OC in rivers. River damming alters the stoichiometric characteristics of water elements, nutrient constraints, aquatic communities composition and the coupling effect of C/N/P/Si. The stable isotopic compositions of C, N and Si can effectively trace the source, migration and transformation of biogenic matter. A combination of elements stoichiometric characteristics and stable isotopic composition could effectively indicate the change of source materials in reservoirs. With the increasing demand for clean energy, the intensity of river damming and reservoir construction will increase. Thus, a series of scientific problems including changing law of biogenic substance migration and transformation dynamic, as well as accumulation effect of ecological environment in watershed systems by river cascade damming, should need to be concerned in the biogeochemistry cycle study.     

Impact of seaweeds on agricultural crop production as biofertilizer

Seaweeds or marine macroalgae are rich in diverse compounds like lipids, proteins, carbohydrates, phytohormones, amino acids, osmoprotectants, antimicrobial compounds and minerals. Their potential for agricultural applications is used since antiquity, but recent demands of organic farming and organic food stimulated much the application of organic treatments like seaweed extracts in agriculture. The benefits of seaweeds application in agricultural field are numerous and diverse such as stimulation of seed germination, enhancement of health and growth of plants namely shoot and root elongation, improved water and nutrient uptake, frost and saline resistance, biocontrol and resistance toward phytopathogenic organisms, remediation of pollutants of contaminated soil and fertilization. In this review, scientific progress in this field was collected and critically assessed to lay grounds for further investigations and applications.